To turn string into code - c++

Question

My english is not very good, but, I hope, you will understand me.
I know that turning string into code is impossible in C++, but I just can't see another way of solving my trouble.
I have an array of structures. You can say that it's a database. The task is that user should make combined request. In console a user chooses two parameters of structure and makes a combined request.
Something like this
cout<<"\nВыберите первый параметр для поиска:" // Choose first parameter
<<"\n1. processor"
<<"\n2. videocard"
<<"\n3. display"
<<"\n4. RAM"
<<"\n5. size"<<endl;
int first;
cin>>first;
cout<<"\nВыберите второй параметр для поиска:" // Choose second parameter
<<"\n1. processor"
<<"\n2. videocard"
<<"\n3. display"
<<"\n4. RAM"
<<"\n5. size"<<endl;
int second;
cin>>second;
cout<<"enter searchkey for first value: "
string search1;
cin>>search1;
cout<<"enter searchkey for second value: "
string search2;
cin>>search2;
string parameters[ 5 ] = { "processor", "videocard", "display", "RAM", "size" };
for ( i = 0; i < size; i++ ) // And that's where it all goes wrong.
if ( arrayOfStructs.parameters[ first ] == search1 && arrayOfStructs.parameters[ second ] == search2 )
cout<<"found a match"<<endl;
I know why code doesn't work. I'm really sure that exists a solution that looks similar to mine. My "solution" looks like enum, but enum in this case is not appropriate.
If you know the solution, please write it down below.
The full code of my program
#include <iostream>
#include <iomanip>
#include <fstream>
#include <string>
#include <sstream>
using namespace std;
struct computer
{
string processor;
string videocard;
string display;
string RAM;
string size;
string getFieldValue( int );
};
string computer::getFieldValue( int fieldNumber )
{
stringstream str;
switch (fieldNumber)
{
case 1: str<<this->processor;
case 2: str<<this->videocard;
case 3: str<<this->display;
case 4: str<<this->RAM;
case 5: str<<this->size;
}
return str.str();
}
void coutAndWrite( computer aStruct, ofstream &aFile );
int main()
{
setlocale( 0, "" );
computer sklad[ 30 ];
computer temp;
int i = 0, j;
ifstream fromFile("structury.txt");
while ( !fromFile.eof() )
{
fromFile>>sklad[ i ].processor
>>sklad[ i ].videocard
>>sklad[ i ].display
>>sklad[ i ].RAM
>>sklad[ i ].size;
i++;
}
fromFile.close();
ofstream rezultaty("rezultaty.txt");
for ( i = 0; i < 30; i++ )
for ( j = 0; j < 29; j++ )
if ( sklad[ j + 1 ].processor[ 0 ] < sklad[ j ].processor[ 0 ] )
{
temp = sklad[ j + 1 ];
sklad[ j + 1 ] = sklad[ j ];
sklad[ j ] = temp;
}
while ( 1 )
{
cout<<"\nВыберите тип запроса:"
<<"\n1. Простой"
<<"\n2. Составной"
<<"\n0. Выход из программы\n";
int prostoiIliSostavnoi;
cin>>prostoiIliSostavnoi;
if ( prostoiIliSostavnoi == 0 )
break;
if ( prostoiIliSostavnoi == 1 )
{
cout<<"\nВыберите параметр для поиска:"
<<"\n1. processor"
<<"\n2. videocard"
<<"\n3. display"
<<"\n4. RAM"
<<"\n5. size"<<endl;
int parametr;
cin>>parametr;
cout<<"Введите ключ поиска: ";
string poisk;
cin>>poisk;
cout<<"Результаты поиска: ";
for ( i = 0; i < 30; i++ )
if ( sklad[ i ].getFieldValue( parametr ) == poisk )
coutAndWrite( sklad[ i ], rezultaty );
}
}
system("pause");
}
void coutAndWrite( computer aStruct, ofstream &aFile )
{
cout<<"\nprocessor: "<<aStruct.processor
<<"\nvideocard: "<<aStruct.videocard
<<"\ndisplay: "<<aStruct.display
<<"\nRAM: "<<aStruct.RAM
<<"\nsize: "<<aStruct.size<<endl<<endl;
aFile<<setw( 15 )<<aStruct.processor
<<setw( 15 )<<aStruct.videocard
<<setw( 20 )<<aStruct.display
<<setw( 10 )<<aStruct.RAM
<<setw( 10 )<<aStruct.size<<endl;
}

Answer 1

Break it into pieces. Let's ignore the loop and the double search, and focus on the core problem: getting a field's value when you have its field number (or name):
string Computer::getFieldValue(int fieldNumber)
{
stringstream str;
switch (fieldNumber) {
case 1: str << this->processor; break;
case 2: str << this->videocard; break;
case 3: str << this->display; break;
case 4: str << this->RAM; break;
case 5: str << this->size; break;
}
return str.str();
}
Given this helper function, it's now possible to write the checking code.
for (int i = 0; i < size; ++i) {
if (computers[i].getFieldValue(first) == search1 &&
computers[i].getFieldValue(second) == search2)
{
cout << "found a match" << endl;
}
}